1. Field of the Invention
This invention generally relates to vacuum cleaner bags, and more specifically to a vacuum cleaner bag construction which includes a collar sealing closure device for selectively and effectively sealing the inlet opening to the bag.
2. Description of the Prior Art
Filter bags require an inlet opening which is dimensioned to accept the inlet fitting of the vacuum cleaner bag through which contaminated air is guided into the vacuum cleaner bag. Efforts have been made to seal the inlet opening both during use, to avoid leakage and insure that all the debris is guided into the bag, and subsequently to avoid backflow or spillage during handling after the bag is removed from the vacuum cleaner. In one common design, a tongue is attached to a rigid or semirigid collar of the vacuum cleaner bag across the inlet opening. The collar is typically made of cardboard (for dispensable bags), or from a more durable material, such as stiff rubber or fiber (for reusable filter bags). However, such tongues must be used in connection with a rubber membrane incorporated into the collar. The tongue is forced through the inlet opening and only partially blocks the inlet opening because of the imperfect seal created by the rubber membrane when it contracts about the tongue. This problem also manifests itself when the bag is removed for replacement and must be handled in the course of being discarded or handled while emptying the contents so that the bag can be reused. Once the filter bag is filled with dust and debris, any pressures applied to the bag during handling creates a problem of a back flow of air which is forced through the imperfect seal above described.
Use of the tongue also has the disadvantage that it creates leakage during use of the bag in a vacuum cleaner when the tongue is lifted away from the inlet opening by the fitting to bear against the rubber membrane and thereby stretch the same. Because the fitting is generally cylindrical and the tongue is generally flat, spaces are created in the transition areas where the membrane moves from the tongue to the fitting. Such leakage releases potentially harmful materials into the bag chamber and draws debris into the motor where sub-atmospheric pressures are created thereby damaging, over extended periods of time, the motor and other operative parts. Numerous design examples of vacuum cleaner bags using such tongues are more fully discussed in co-pending application Ser. No. 07/329,360, filed on Mar. 27, 1989, and assigned to the assignee of the subject application. In all cases, however, the tongue cannot be positively locked after the bag is removed, thereby providing unreliable sealing that may vary from bag to bag.
The above-mentioned designs are particularly objectionable when the collected dust may be contaminated with germs (hotels, hospitals, etc.) or consists of hazardous materials (e.g. asbestos).